lowering kit and rim choice

Hey everyone ,I have a 71 yellow mach 1. I was saving up for coilovers n going for a retro mach 1 but might have to buy a new car first. So I was wondering does someone Make a lowering kit front and back ? I need new rear springs bc mine are sagging but figured I would see if i can get a full lowering kit. Also wanted to see what wheels you guys think I should go with the regular Magnum 500s since I have the dog dish wheels now or the American racing vn 500 wheels. Also if anyone can point me in the direction for the best deal thank you very much

These are mine 15 x 7 with 4 inches bs, with 26 x 8 tires front and 15 x 10 with 5.5 inches bs, with 28 x 12 tires rear